Sucrose, C12H22O11, a disaccharide, is a condensation molecule that links one glucose monosaccharide and one fructose monosaccharide. Sucrose occurs naturally in many fruits and vegetables of the plant kingdom, such as sugarcane, sugar beets, sweet sorghum, sugar palms, or sugar maples. The amount of sucrose produced by plants can be dependent on the genetic strain, soil or fertilization factors, weather conditions during growth, incidence of plant disease, degree of maturity or the treatment between harvesting and processing, among many factors.
Sucrose may be concentrated in certain portions of the plant. For example, sucrose is concentrated in the stalks of the sugarcane plant and in the root of the sugar beet. The entire plant, or the portion of the plant in which the sucrose is concentrated, may be harvested and the plant juices may be removed or extracted to obtain a process liquid containing a certain concentration of sucrose. Typically, the removal or extraction of juices from plant material involves milling, diffusion, pressing, individually or in combination.
Milling is one of the conventional methods for extracting juice from sugar cane stalks. The sugar cane stalks may be cut up into pieces having the desired size and then passed through rollers to squeeze out the juices. This process may be repeated several times down a series of mills to ensure that substantially all the sugar cane juice is removed.
Diffusion is considered to be the conventional method for extracting juice from the root of the sugar beet. Sugar beets may be sliced into thin strips called “cossettes” that can be introduced into one end of a diffuser while a diffusion liquid, such as warm water, enters the other end of the diffuser. When such counter current processing is used about 98 percent of the sucrose from the cossette or sugar beet material can be removed. The resulting sucrose containing process liquid is often called “diffusion juice.” The cossettes or beet slices from the diffuser can still be very wet and the juice, which can be 88–92% water, associated with them can still hold some sucrose. The cossettes or beet slices may, therefore, be pressed in a screw press, or other type of press, to squeeze as much juice out of them as possible. This process liquid often referred to as “pulp press water” can have a pH value of about 5 and in some cases is returned to the diffuser. The resulting pulp may contain about 75% moisture. The addition to the press feed of cationic charged pressing aids can be used to lower the pulp moisture content by about 1.5 to 2%. Sucrose from sugarcane stalks can also be removed by diffusion. One diffusion process for sugarcane involves a moving bed of finely prepared sugarcane pieces passed through the diffuser allowing the sucrose to be leached out of the sugarcane.
The diffusion process, the milling process, other processes that remove juice from plant material result in a process liquid containing sucrose, non-sucrose substances, and water. The nature and amount of the non-sucrose substances in the juice obtained by these processes can vary and may include all manner of plant derived substances and non-plant derived substances, including but not limited to: insoluble material, such as, plant fiber or soil particles; and soluble materials, such as, fertilizer, sucrose, saccharides other than sucrose, organic and inorganic non-sugars, organic acids, dissolved gases, proteins, inorganic acids, organic acids, phosphates, metal ions (for example, iron, aluminum, or magnesium ions), pectins, colored materials, saponins, waxes, fats, or gums, their associated or linked moieties, or derivatives thereof.
These non-sucrose substances are often highly colorized, thermally unstable, or otherwise interfere with certain processing steps or adversely impact the quality or quantity of the sugar product resulting from the purification process. It has been estimated that on average one pound of non-sucrose substances reduces the quantity of sugar product resulting from the purification process by one and one-half pounds. It may be desirable to have all or a portion of these non-sucrose substances separated from or removed from the process liquid resulting from the diffusion, milling, or other methods used to remove juice from the plant material. A good diffusion operation can eliminate 25–30% of entering impurities. Returned pulp or carbonation press water can reduce this level to 17–20%, and can be economical due to heat recovery, make up water saved, wastewater pollution reduced, or additional sugar recovered.
Process systems, including the embodiments of the invention described herein, or those described by U.S. Pat. Nos. 6,051,075; 5,928,42; 5,480,490, each hereby incorporated by reference, or those described by “Sugar Technology, Beet and Cane Sugar Manufacture” by P. W. van der Poel et al. (1998); “Beet-Sugar Technology” edited by R. A. McGinnis, Third Edition (1982); or Cane Sugar Handbook: A Manual for Cane Sugar Manufacturers and Their Chemists by James C. P. Chen, Chung Chi Chou, 12th Edition (1993), each hereby incorporated by reference herein, utilize the remaining plant material and the juice(s) obtained from the plant material to generate various types of: process liquids; solids from the remaining plant material; solids separated from the process liquids during clarification, purification or refining; sugar or sucrose containing juices; crystallized sugar or sucrose; mother liquors from crystallization of sugar or sucrose; by products of the process system; and various combinations, permutations, or derivatives thereof, each having a level of impurities consistent with the process steps utilized in their production, or consistent with conventional standards for that type or kind of product produced, including, but not limited to: animal feeds containing exhausted plant material, such as, exhausted beet cossettes, pulp, or bagasse or other solids or juices separated from process liquids; solid fuel which can be burned to generate steam for electrical power production, or to generate low pressure steam that can be returned to the sugar process system, or to generate low grade heat; syrup ranging from pure sucrose solutions such as those sold to industrial users to treated syrups incorporating flavors and colors, or those incorporating some invert sugar to prevent crystallization of sucrose, for example, golden syrup; molasses obtained by removal of all or any part of the crystallizable sucrose or sugar, or products derived from molasses, one example being treacle; alcohol distilled from molasses; blanco directo or plantation sugars generated by sulfitation using sulfur dioxide (SO2) as a bleaching agent; juggeri or gur generated by boiling sucrose or sugar containing juices until essentially dry; juice sugar from melting refined white sugar or from syrup(s) which may be further decolorized; single-crystallization cane sugars often referred to as “unrefined sugar” in the United Kingdom or other parts of Europe, or referred to as “evaporated cane juice” in the North American natural foods industry to describe a free-flowing, single-crystallization cane sugar that is produced with a minimal degree of processing; milled cane; demerara; muscovado; rapedura; panela; turbina; raw sugar which can be about 94–98 percent sucrose, the balance being molasses, ash, and other trace elements; refined sugars such as extra fine granulated having a quality based upon “bottlers” quality specified by the National Soft Drink Association being water white and at least 99.9 percent sucrose; specialty white sugars, such as, caster sugar, icing sugar, sugar cubes, or preserving sugar, brown sugars that can be manufactured by spraying and blending white refined sugar with molasses which can be light or dark brown sugar depending on the characteristics of the molasses; or powdered sugar made in various degrees of fineness by pulverizing granulated sugar in a powder mill and which may further contain corn starch or other chemicals to prevent caking. This list is not meant to be limiting with respect to the products generated from the juices or process liquids obtained, removed or extracted from plant material, but rather, it is meant to illustrative of the wide variety and numerousity of products that can be generated from conventional process systems or process systems in accordance with the inventions described herein.
As can be understood, process systems, in part, comprise steps that increasingly clarify, purify, or refine process liquids resulting from the diffusion, milling, or other methods used to remove juice from the plant material. Typically, a portion of the insoluble or suspended material in process liquids containing juice derived from plant material can be removed using one or more mechanical processes such as screening. The resulting screened process liquid, when derived from sugar beets may contain about 82%–85% by weight water, about 13–15% by weight sucrose, about 2.0–3.0% by weight dissolved non-sucrose substances or impurities, and some amount of remaining insoluble materials.
Typically, the process liquid obtained by removing juices from plant material, which can have a volume of 1000–2500 gallons per minute, is treated by the gradual addition of a base to increase the pH. In certain conventional process systems, the pH of the process liquid may be raised from a range between about 5.5 pH to about 6.5 pH up to a range of between about 11.5 pH to about 11.8 pH which enables certain non-sucrose substances contained in the process liquid to reach their respective iso-electric points. In conventional sugar process systems, this step is often referred to as “preliming”. However, the subsequent use of the term “preliming” is not meant to limit the step of adding base to process liquids solely to the addition of lime, or solely to those process systems that use lime, or solely to those methods that refer to the addition of base as “preliming”. Rather, it should be understood that the term “preliming” as used herein includes the step of adding base to process liquids in all various types of processing systems to affect a reduction in concentration of certain soluble components in the process liquid, or to raise the pH of the process liquid, and the term “preliming” can be used to describe the addition of base (lime or otherwise) prior to a filtration step, as described by U.S. Pat. Nos. 4,432,806, 5,759,283, or the like; an ion exchange step as described in British Patent No. 1,043,102, or U.S. Pat. Nos. 3,618,589; 3,785,863; 4,140,541; 4,331,483; 5,466,294, or the like; a chromatography step as described by U.S. Pat. Nos. 5,466,294; 4,312,678; 2,985,589; 4,182,633; 4,412,866; 5,102,553, or the like; or an ultrafilitration step as described by U.S. Pat. No. 4,432,806, or the like; phase separation step as described by U.S. Pat. No. 6,051,075, or the like; addition of active materials to the final carbonation vessel as described by U.S. Pat. No. 4,045,242; each reference hereby incorporated by reference herein, or can be used to describe the addition of lime to process liquids to generate precipitates for the purpose of clarifying.
The use of the term “base” involves the use materials that are capable of increasing the pH of a process liquid including, but not limited to, the use of lime or the underflow from processes that utilize lime. The use of the term “lime” typically involves the specific use of quick lime or calcium oxides formed by heating calcium (generally in the form of limestone) in oxygen to form calcium oxide. Milk of lime is preferred in many juice process systems, and consists of a suspension of calcium hydroxide (Ca(OH)2) in accordance with the following reaction:CaO+H2O═Ca(OH)2+15.5 Cal.
The term “iso-electric point” involves the pH at which dissolved or colloidal materials, such as proteins, within the juice have a zero electrical potential. When such dissolved or colloidal materials reach their designated iso-electric points, they may form a plurality of solid particles, flocculate, or flocs.
Flocculation may be further enhanced by the addition of calcium carbonate materials to juice, which functionally form a core or substrate with which the solid particles or flocculates associate. This process increases the size, weight or density of the particles, thereby facilitating the filtration or settling of such solid particles or materials and their removal from the process liquid.
The resulting prelimed process liquid containing residual lime, excess calcium carbonate, solid particles, flocculants, or flocs, may then be subjected to subsequent process steps as described above. Specifically, with regard to the process system for the clarification, purification, or refining of process liquids from sugar beets, the mixture may first be subjected to a cold main liming step to stabilize the solids formed in the preliming step. The cold main liming step may involve the addition of about another 0.3–0.7% lime by weight of prelimed process liquid (or more depending on the quality of the prelimed juice) undertaken at a temperature of between about 30 degrees Centigrade (° C.) to about 40° C.
The cold main limed process liquid may then be hot main limed to further degrade invert sugar and other components that are not stable to this step. Hot main liming may involve the further addition of lime to cause the pH of the limed juice to increase to a range between about 12.0 pH to about 12.5 pH. This results in a portion of the soluble non-sucrose materials that were not affected by preceding addition of base or lime to decompose. In particular, hot main liming of the limed process liquid may achieve thermostability by partial decomposition of invert sugar, amino acids, amides, and other dissolved non-sucrose materials.
After cold or hot main liming, the main limed process liquid can be subjected to a first carbonation step in which carbon dioxide gas can be combined with the main limed process liquid. The carbon dioxide gas reacts with residual lime in the main limed process liquid to produce calcium carbonate in the form of precipitate. Not only may residual lime be removed by this procedure (typically about 95% by weight of the residual lime), but also the surface-active calcium carbonate precipitate may trap substantial amounts of remaining dissolved non-sucrose substances. Furthermore, the calcium carbonate precipitate may function as a filter aid in the physical removal of solid materials from the main limed and carbonated process liquid.
The clarified process liquid obtained from the first carbonation step may then be subjected to additional liming steps, heating steps, carbonation steps, filtering steps, membrane ultrafiltration steps, chromatography separation steps, or ion exchange steps as above described, or combinations, permutations, or derivations thereof, to further clarify or purify the juice obtained from the first carbonation step resulting in a process liquid often referred to as “thin juice”.
This further clarified process liquid or “thin juice” may be thickened by evaporation of a portion of the water content to yield a product conventionally referred to as “syrup”. Evaporation of a portion of the water content may be performed in a multi-stage evaporator. This technique is used because it is an efficient way of using steam and it can also create another, lower grade, steam which can be used to drive the subsequent crystallization process, if desired.
The thickened clarified process liquid or “syrup” can be placed into a container, which may typically hold 60 tons or more. In the container, even more water is boiled off until conditions are right for sucrose or sugar crystals to grow. Because it may be difficult to get the sucrose or sugar crystals to grow well, some seed crystals of sucrose or sugar are added to initiate crystal formation. Once the crystals have grown the resulting mixture of crystals and remaining juice can be separated. Conventionally, centrifuges are used to separate the two. The separated sucrose or sugar crystals are then dried to a desired moisture content before being packed, stored, transported, or further refined, or the like. For example, raw sugar may be refined only after shipment to the country where it will be used.
There is a competitive global commercial market for the products derived from sugar process systems as described above. The market for such products has sufficient size that even a slight reduction in the cost of a single process system step can yield a substantial and desired monetary savings. As such, there is great incentive to the sugar industry to perform research to provide improvements for sugar process systems which yield process system savings. Often independent researchers and product distributors are paid for novel process system chemicals, equipment, or process methods, and in some cases a further incentive is provided by additional payments based upon percentage of the savings within the sugar process system due to improvements made.
However, even though process systems for the purification of juice from plant materials have been established and improved upon for at least 1000 years, and specifically with regard to sugar beets, have been improved upon for more than 100 years, and even though there is great incentive to generate improvements relating to sugar process systems, significant problems still remain with regard to the processing of juices obtained from plant material.
A significant problem with conventional sugar processing systems can be the expense of obtaining and adding base, such as calcium oxide, to process liquids to raise the pH of process liquids or to reduce the concentration of acids. As discussed above, calcium oxide or calcium hydroxide may be added to process liquid to raise the pH allowing certain materials in the process liquid to be removed, such as solids, flocculent, or flocs. Calcium oxide is typically obtained through calcination of limestone a process in which the limestone is heated in a kiln in the presence of oxygen until carbon dioxide is released resulting in calcium oxide.
Calcination can be expensive because it requires (as shown by FIG. 5) the purchase of a kiln (40), limestone (41), and fuel (42), such as gas, oil, coal, coke, or the like, that can be combusted to raise the temperature of the kiln sufficiently to release carbon dioxide (43) from the limestone (41). Ancillary equipment to transport the limestone and the fuel to the kiln and to remove the resulting calcium oxide from the kiln must also be provided along with equipment to scrub certain kiln gases and particles from the kiln air exhausted during calcination of the limestone. Naturally, labor must be provided to operate and maintain the equipment, as well as, monitor the quality of the calcined limestone generated and also to monitor the clean up of gases and particulates released during operation of the kiln.
Additionally, the calcium oxide generated by calcination must be converted to calcium hydroxide for use in typical juice process systems. Again this involves the purchase of equipment to reduce the calcium oxide to suitably sized particles and to mix these particles with water to generate calcium hydroxide. Again, labor must be provided to operate and maintain this equipment.
Finally, the investment in equipment and labor associated with the use of calcium oxides incrementally increases as the amount used increases. This may involve the incremental expenditure for the additional labor to mix additional amounts of calcium hydroxide with process liquids, or it may involve an incremental expenditure to use equipment having greater loading capacity or having greater power, or the like.
Another significant problem with the production of and use of base, such as lime, in conventional sugar process systems can be disposal of excess base, spent lime, or process byproducts formed with added base. For example, when the process system uses one or more carbonation steps in clarifying or purifying juice, the amount of calcium carbonate or other salts formed, often referred to as “spent lime”, will be proportionate to the amount of lime added to the process liquid. Simply put, the greater the amount of lime added to the process liquid, generally the greater the amount of precipitates formed during the carbonation step. The “carbonation lime” may be allowed to settle to the bottom of the carbonation vessel forming what is sometimes referred to as a “lime mud”. Lime mud can be separated by a rotary vacuum filter or plate and frame press. The product formed is then called “lime cake”. Lime cake or lime mud is largely calcium carbonate precipitate but may also contain sugars, other organic or inorganic matter, or water. These separated precipitates are almost always handled separately from other process system wastes and may, for example, be slurried with water and pumped to settling ponds or areas surrounded by levees or transported to land fills.
Alternately, the carbonation lime, lime mud, or lime cake can be recalcined. However, the cost of a recalcining kiln and the peripheral equipment to recalcine spent lime can be substantially more expensive than a kiln for calcining limestone. Furthermore, the quality of recalcined “carbonation lime” can be different than calcined limestone. The purity of calcined limestone compared to recalcined carbonation lime may be, as but one example, 92% compared with 77%. As such, the amount of recalcined lime required to neutralize the same amount of hydronium ion in juice may be correspondingly higher. Also, the carbon dioxide content of spent lime can be much higher than limestone. As such, not only can recalcined lime be expensive to generate, it can also require the use of substantially larger gas conduit to transfer the generated CO2 from recalcining spent lime, larger conveying equipment to move the recalcined lime, larger carbonation tanks, or the like.
Also whether spent lime is disposed of in ponds, landfills, or by recycling, the greater the amount of lime utilized in a particular process system, generally the greater the expense of disposing the spent lime.
Another significant problem with conventional sugar processing systems that use base or lime to purify or clarify process liquids may be an incremental decrease in process system throughput corresponding with an incremental increase in the amount of lime used in processing liquids. One aspect of this problem may be that there is a limit to the amount of or rate at which lime can be produced or provided to juice process steps. As discussed above, limestone must be calcined to produce calcium oxide prior to its use as a base in juice process systems. The amount of lime produced may be limited in by availability of limestone, kiln capacity, fuel availability, or the like. The rate at which lime can be made available to the juice process system may vary based on the size, kind, or amount of the lime generation equipment, available labor, or the like. Another aspect of this problem can be that the amount of lime used in the process system may proportionately reduce volume available for juice in the process system. Increased use of base, such as lime, may also require the use of larger containment areas, conduits, or the like to maintain throughput of the same volume of juice.
The amount of base or lime used during conventional sugar processing depends in part upon the amount of acids associated with the plant material at the time of removal or extraction of the juice. Organic acids act as a buffering system in the acid-base equilibrium of the plant cell, in order to maintain the required pH value in the plant tissue. The origin of these acids can be divided into two groups, the first, are acids taken up by the plant from the soil in the course of the growing cycle, and the second, are acids formed by biochemical or microbial processes. When the uptake of acids from the soil is insufficient, plants may synthesize organic acids, primarily oxalic acid, citric acid and malic acid, to maintain a healthy pH value of the plant cell juice. As such, juice extracted from the plant tissue will contain a certain amount of various organic acids. In addition to this naturally occurring amount of organic acids within the plant tissue, acids may be formed during storage primarily by microbial processes. Badly deteriorating plant material may generate large amounts of organic acids, primarily lactic, acetic acid, as well as citric acid. The total acid content within the plant tissue can increase threefold, or more, under certain circumstances.
Additionally, carbon dioxide (CO2) can be generated in the plant tissues due to breakdown of the natural alkalinity in the juice. In this process, bicarbonate ion and carbonate ion are converted to carbon dioxide. The resulting carbon dioxide, to the extent it remains in solution, generates carbonic acid that provides a source of hydronium ion. Organic acids contained within the plant cell juice, in whole or in part, remain within the juice obtained from the plant material. As such, to raise the pH of the process liquid containing juice, these acids must be neutralized with base. The higher the concentration of such acids in the process liquid, the greater the amount of base required to raise the pH of the process liquid to a desired value.
Moreover, plant materials, juice(s), or process liquids treated with antimicrobial chemicals can have higher acid content then untreated plant materials or juices. For example, sulfur dioxide (SO2) or ammonium bisulfite (NH4HSO3) can be added continuously or intermittently to help control microbial growth or infection. The amount of SO2 or NH4HSO3 added depends on the severity of the microbial growth or infection. Lactic acid and nitrite levels can be monitored or tracked to determine severity of growth or infection. Up to about 1000 ppm of SO2 can be used to shock or treat an infected system. Up to 400–500 ppm can be fed continuously to control an infection. The SO2 or NH4HSO3 addition used for antimicrobial protection can further lower the pH and alkalinity of juice(s) or process liquids. The alkalinity reduction may occur due to conversion of naturally occurring bicarbonate ions to CO2 and carbonic acid.
Another significant problem with conventional sugar process systems may be that juice(s) or process liquids may contain other undesired components, or components that are at concentrations that are undesirably high. These undesired components may include components of natural origin such as fermentation products, such as ethanol, isobutanol, isoamyl alcohol, propanol, other volatile or semi-volatile organic compounds, or the like. Alternately, undesired components may be of non-natural origin such as antimicrobial agents, anti-foaming agents, or the like. These undesired components are typically reduced in concentration during liming steps, or evaporation steps, or removed as part of the mother liquor of crystallization.
Another significant problem with conventional sugar processing systems may be the formation of scale in containment vessels, such as, evaporators or sugar crystallization equipment. The calcium salt of oxalic acid often forms the main component of scale. Oxalate has low solubility in solution and that solubility can be reduced as the amount of calcium in solution increases. Even after juice purification to “thin” or “thick” juices there can be sufficient calcium in solution to force oxalate out of solution. The process of removing scale from the surfaces of equipment can be expensive, including, but not limited to, costs due to production slowdowns and efficiency losses, or the reduction in the effective life of equipment.
Another significant problem with convention sugar processing systems may be the lack of recognition that juice extraction equipment or processes used to obtain juice from plant material can lower the pH of the extracted juice. With respect to diffusors used to extract juice from sugar beet root, there may have been a failure to recognize that the pH value of sugar beet juice or process liquids can be significantly lowered during the diffusion process. Another aspect of this problem may be that there has been a lack of recognition that different diffusion apparatus or different diffusion methods used to remove juice from sugar beet material differentially alters or reduces the pH of the juice or process liquid obtained. To the extent that improvements in diffusion technology have resulted in increasingly lower pH values of the juice or process liquid obtained, these apparatuses and methods teach away from the solutions provided by the invention.
Another significant problem with conventional sugar processing systems may be that organic compounds, inorganic compounds, organic acids, inorganic acids, dissolved gases, or other materials contained within extracted juice or process liquids, whether of natural origin or added to the extracted juice or process liquids, may not be allowed to move toward equilibrium to with atmospheric partial pressures of gases, or other mixture of partial pressures of gases to the extent possible or desirable. As such, an amount of these various components that could have been transferred from the juice or process liquid to the atmosphere or other mixture of partial pressures of gases remain in the juice or process liquid. The increased concentration of these components can contribute to lower pH of the juice or process liquid or remain in the process liquid to precipitate, form scale, or necessitate removal in subsequent process system steps. Lower pH can result in the use of additional base or lime, as described above, to achieve the desired pH of the juice.
One aspect of this problem with respect to conventional diffusion of sugar beet cossettes (or other conventional methods of removing or extracting juice or material(s) from plant material(s)) may be that conventional diffusion equipment (or other conventional equipment used to remove or extract juice or other materials from plant material(s)) does not provide, or provides an inadequate, process liquid-gas interface between the diffusion juice(s) or process liquids and atmospheric partial pressure of gases, or other present mixture of partial pressures of gases. Whether due to the equipment used or the method employed conventional process systems do not allow transferable components in the process liquid to move toward an equilibrium with existing or atmospheric partial pressures of gases that would substantially reduce the concentration of such components in the diffusion juice or process liquids.
A second aspect of this problem may be that conventional sugar process methods or equipment (or other conventional equipment used to remove or extract juice or other materials from plant material(s)) do not provide sufficient re-circulation of atmospheric partial pressures, or other desired or selected partial pressures of gases, within process equipment to maintain a sufficient difference in partial pressures between the concentration of material(s) in the juice or process liquid and the partial pressures of gases presented at the process liquid-gas interface to generate a concentration gradient effective in achieving the desired, potential, or possible mass transfer of materials to effect the desired, potential, or possible reduction of pH in the juice or process liquid. As such, a desirable equilibrium or complete equilibrium between the partial pressures of gases presented at the process liquid-gas interface and the partial pressures of materials can be prevented or slowed which in turn can generate juice or process liquids that require more base or lime addition to reach a desired pH value or contain an incremental amount of additional material that must be removed in subsequent processing steps.
A third aspect of this problem may be that conventional sugar process methods or equipment (or other conventional equipment or methods used to remove or extract juice or other materials from plant material(s)) do not sufficiently mix juice or process liquids to allow the entire volume, or a sufficient volume, to move toward equilibrium with the atmosphere or other mixture of gases presented at the process liquid-gas interface.
A fourth aspect of this problem may be that conventional sugar process methods or equipment (or other conventional equipment or methods used to remove or extract juice or other materials from plant material(s)) do not heat the juice(s) or other process liquids to a temperature that sufficiently reduces the solubility of undesired components in the juice or process liquid to allow sufficient mass transfer of such undesired components from the juice or process liquid to the partial pressures of gases presented at the process liquid-gas interface, or move the point of equilibrium such that the concentration of pH reducing materials can be reduced to the desired, potential, or possible concentration, or move toward or equilibrate with the partial pressure of gases presented to the process liquid-gas interface at the rate desired, or at the potential or possible equilibration rate that may be desired or achieved.
Another significant problem with conventional sugar processing systems may be that extracted juice(s) or process liquids are allowed to move toward equilibrium or equilibrate with atmospheric partial pressures or with other mixture of gases having higher concentration of undesired components or pH reducing materials as the extracted juice or process liquid cools. As extracted juice, such as diffusion juice, or process cool the solubility of atmospheric gases or other mixture of gases presented at the process liquid-gas interface can increase. As such, the undesired gases or other volatile materials can be transferred into the juice (including but not limited to pH reducing materials) may increase as the diffusion juice cools. As but a single example, solubility of atmospheric CO2 increases as diffusion juice cools from a range of between about 55° C. to about 70° C. during diffusion steps to a range of temperature between about 20° C. to 30° C. prior to the pre-liming or liming steps. Exposure to atmospheric partial pressures of CO2, or any mixture of gases having sufficient partial pressure of CO2 to allow transfer of CO2 to the juice as it cools, increases the concentration of CO2 in the diffusion juice relative to that amount present at higher temperatures. The increased concentration of CO2 in the diffusion juice may reduce the pH of the juice. As such, the increased concentration of CO2 or other gases in the diffusion juice may require addition of greater amounts of lime during subsequent lime addition, pre-liming or other liming steps to achieve a desired or necessary pH.
Another significant problem with conventional sugar processing systems may be that the partial pressures of gases presented at the process liquid-gas interface are not effective in establishing a concentration gradient sufficient to transfer, move, or remove the necessary or desired portion of materials or components from the diffusion juice or other process liquid or to substantially increase the pH of the diffusion juice or reduce the concentration of pH reducing materials in the diffusion juice.
The present invention provides a juice process system involving both apparatuses and methods that address each of the above-mentioned problems.